MEC E563 Lecture Notes - Lecture 3: Free Body Diagram, Matrix Multiplication, Structural Mechanics

• School: University of Alberta
• Department: Mechanical Engineering
• Course: MEC E563
• Professor: Walied Moussa

Document Summary

Chapter 2 covered the initial steps of the dsm. The three breakdown steps: disconnection, local- ization and formation of member stiffness take us down all the way to the generic truss element: the highest level of fragmentation. This is followed by the assembly and solution stage. Assembly involves merging the stiffness equations of each member into the global stiffness equa- tions. For this to make sense, the member equations must be referred to a common coordinate system, which for a plane truss is the global cartesian system {x , y}. This is done through the globalization process covered in 2. 10. On the computer the formation, globalization and merge steps are done concurrently, member by member. After all members are processed we have the free-free master stiffness equations. This process embodies two steps: applying boundary conditions (bc), and solving for the unknown joint displacements.